Commitments and Contingencies Narrative (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 lease	Jun. 30, 2012	Dec. 31, 2011 lease	Dec. 31, 2012
Long-term Purchase Commitment [Line Items]
Operating lease payments	$ 193	$ 136	$ 384,000	$ 264,000
Number of non-cancelable lease agreements			3		2
Depreciation expense on the equipment under the capital leases	40	30	79	59
Current portion of capital lease	259		259			240
Capital lease, net of current portion	129		129			231
Comerica Bank [Member]
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding, amount	57		57
Comerica Bank [Member] | Subsequent Event [Member]
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding, amount	185		185
Lease 1 [Member]
Long-term Purchase Commitment [Line Items]
Value of non-cancelable capital lease agreements	38		38		512	90
Interest rates on non-cancelable capital lease agreements	8.80%		8.80%		6.00%	9.00%
Lease 2 [Member]
Long-term Purchase Commitment [Line Items]
Value of non-cancelable capital lease agreements					40	30
Interest rates on non-cancelable capital lease agreements					0.00%	3.00%
Lease 3 [Member]
Long-term Purchase Commitment [Line Items]
Value of non-cancelable capital lease agreements						$ 48
Interest rates on non-cancelable capital lease agreements						0.00%